The perils of Cc revisited

The space groups of 98 structures originally reported in Cc are revised. In 75 cases the revised space group is C2/c and the revision entails adding a center of symmetry, usually leading to large changes in bond lengths and angles. In the remaining 23 cases, where the revised space group is Fdd2, R3c or (in one case) Ic2, the lattice type is changed but no center is added; in these cases the molecular dimensions are effectively unchanged.